In industrial processes, component surfaces are typically exposed to environments that erode or contribute to build-up on such surfaces. Thus, new components must be cleaned before first use, and over time, surfaces of such components must be cleaned in order for them to continue to be useful. Otherwise, such surfaces (or whole components) must be replaced. Due to cost concerns, cleaning a surface is often preferable to replacement. However, certain surfaces are difficult to clean due to the nature of the component and the environment to which it is exposed. For example, semiconductor substrate materials (such as silicon wafers) are processed in plasma processing chambers wherein interior and interior-facing surfaces are exposed to deposition, etching, and stripping environments. Thus, accumulation of inorganic and organic contaminates on component surfaces is commonly observed and can cause product contamination, reduction in processing efficiency, or both.
One example of a surface in a plasma processing chamber is a quartz (SiO2) surface. Chamber components having such a surface include, but are not limited to, windows and view ports (collectively, “windows”). Through the processing of semiconductor substrate materials, organic materials (for example, finger oils, grease, particles and organic compounds); metals (for example, aluminum, molybdenum, and tungsten); dielectric materials (for example, silicon dioxide and silicon nitride); and other inorganic materials can become deposited onto such windows. Such windows are typically cleaned in an ultrasonic bath. However, conventional baths and cleaning methods suffer from an inability to provide particle-free, or consistently particle-free, results. This is because such baths and methods fail to remove all particles from the window or some of the particles that do get removed recirculate in the bath and redeposit on the window.
Whether cleaning plasma processing chamber components or other articles, there remains a need for better cleaning apparatuses and methods of obtaining ultra-clean articles.